/* SPDX-License-Identifier: GPL-2.0 OR Linux-OpenIB *//* Copyright (c) 2026, NVIDIA CORPORATION & AFFILIATES. */ #ifndef _RDMA_ITER_H_#define _RDMA_ITER_H_ #include <linux/scatterlist.h>#include <rdma/ib_umem.h> /** * IB block DMA iterator * * Iterates the DMA-mapped SGL in contiguous memory blocks aligned * to a HW supported page size. */struct ib_block_iter {	/* internal states */	struct scatterlist *__sg;	/* sg holding the current aligned block */	dma_addr_t __dma_addr;		/* unaligned DMA address of this block */	size_t __sg_numblocks;		/* ib_umem_num_dma_blocks() */	unsigned int __sg_nents;	/* number of SG entries */	unsigned int __sg_advance;	/* number of bytes to advance in sg in next step */	unsigned int __pg_bit;		/* alignment of current block */}; void __rdma_block_iter_start(struct ib_block_iter *biter,			     struct scatterlist *sglist,			     unsigned int nents,			     unsigned long pgsz);bool __rdma_block_iter_next(struct ib_block_iter *biter); /** * rdma_block_iter_dma_address - get the aligned dma address of the current * block held by the block iterator. * @biter: block iterator holding the memory block */static inline dma_addr_trdma_block_iter_dma_address(struct ib_block_iter *biter){	return biter->__dma_addr & ~(BIT_ULL(biter->__pg_bit) - 1);} /** * rdma_for_each_block - iterate over contiguous memory blocks of the sg list * @sglist: sglist to iterate over * @biter: block iterator holding the memory block * @nents: maximum number of sg entries to iterate over * @pgsz: best HW supported page size to use * * Callers may use rdma_block_iter_dma_address() to get each * blocks aligned DMA address. */#define rdma_for_each_block(sglist, biter, nents, pgsz)		\	for (__rdma_block_iter_start(biter, sglist, nents,	\				     pgsz);			\	     __rdma_block_iter_next(biter);) static inline void __rdma_umem_block_iter_start(struct ib_block_iter *biter,						struct ib_umem *umem,						unsigned long pgsz){	__rdma_block_iter_start(biter, umem->sgt_append.sgt.sgl,				umem->sgt_append.sgt.nents, pgsz);	biter->__sg_advance = ib_umem_offset(umem) & ~(pgsz - 1);	biter->__sg_numblocks = ib_umem_num_dma_blocks(umem, pgsz);} static inline bool __rdma_umem_block_iter_next(struct ib_block_iter *biter){	return __rdma_block_iter_next(biter) && biter->__sg_numblocks--;} /** * rdma_umem_for_each_dma_block - iterate over contiguous DMA blocks of the umem * @umem: umem to iterate over * @pgsz: Page size to split the list into * * pgsz must be <= PAGE_SIZE or computed by ib_umem_find_best_pgsz(). The * returned DMA blocks will be aligned to pgsz and span the range: * ALIGN_DOWN(umem->address, pgsz) to ALIGN(umem->address + umem->length, pgsz) * * Performs exactly ib_umem_num_dma_blocks() iterations. */#define rdma_umem_for_each_dma_block(umem, biter, pgsz)                        \	for (__rdma_umem_block_iter_start(biter, umem, pgsz);                  \	     __rdma_umem_block_iter_next(biter);) #endif /* _RDMA_ITER_H_ */